Guardian Sanctuary utility spell bugged
That’s not a bug.
Sanctuary is a small bubble which absorbs projectiles, dont let unfriendly ppl cross it and heals friendly ppl.
This does not mean, that you cant get killed in there. People can still hit you with ground target skills as well as melee attacks. It isnt that easy to hit in melee cause you might get knocked back, but its possible. And you can cross sanctuary with stability.
So nope, there is no bug, you just dont understand the mechanic around that skill.